Apparatus and method for reference signal power boosting in a wireless communication system

ABSTRACT

The disclosure relates to a pre-5 th -Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4 th -Generation (4G) communication system such as Long Term Evolution (LTE). According to an embodiment of the disclosure, a method for operating a user equipment (UE) in a wireless communication system includes determining power of at least one phase tracking reference signal (PT-RS), and transmitting the at least one PT-RS according to non-codebook based transmission. Herein, the power is determined based on a number of at least one port for the at least one PT-RS.

CROSS-REFERENCE TO RELATED APPLICATION AND PRIORITY CLAIM

This application is based on and claims priority under 35 U.S.C. § 119to United Kingdom Patent Application No. 1805051.8 filed on Mar. 28,2018, the disclosure of which is incorporated by reference herein in itsentirety.

BACKGROUND 1. Field

The disclosure relates to a wireless communication system. Moreparticularly, the disclosure relates to an apparatus and a method forboosting power of reference signals in a wireless communication system.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4^(th) generation (4G) communication systems, efforts havebeen made to develop an improved 5^(th) generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘beyond 4G network’ or a ‘post long term evolution(LTE) system’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques are discussed in5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, hybrid frequency shift keying (FSK) and quadratureamplitude modulation (FQAM) and sliding window superposition coding(SWSC) as an advanced coding modulation (ACM), and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have beendeveloped.

In 5G new radio (NR) systems, the power of the phase tracking referencesignal (PTRS) may be used to address common phase error (CPE). Herein,the PTRS may be boosted to improve CPE accuracy. Power boosting for PTRSin codebook-based UL transmission has been agreed in standardizationmeetings.

SUMMARY

According to the disclosure there is provided an apparatus and method asset forth in the appended claims. Other features of the disclosure willbe apparent from the dependent claims, and the description whichfollows.

According to an embodiment of the disclosure, a method for operating auser equipment (UE) in a wireless communication system is provided. Themethod includes determining power of at least one phase trackingreference signal (PT-RS), and transmitting the at least one PT-RSaccording to non-codebook based transmission. Herein, the power isdetermined based on a number of at least one port for the at least onePT-RS.

According to an embodiment of the disclosure, A UE in a wirelesscommunication system is provided. The UE includes a transceiver, and atleast one processor coupled to the transceiver. The at least oneprocessor is configured to determine power of at least one PT-RS, andtransmit the at least one PT-RS according to non-codebook basedtransmission. Herein, the power is determined based on a number of atleast one port for the at least one PT-RS.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout thispatent document, those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosure and its advantages,reference is now made to the following description taken in conjunctionwith the accompanying drawings, in which like reference numeralsrepresent like parts:

FIG. 1 illustrates a wireless communication system according to anembodiment of the disclosure;

FIG. 2 illustrates a base station in a wireless communication systemaccording to an embodiment of the disclosure;

FIG. 3 illustrates a terminal in a wireless communication systemaccording to an embodiment of the disclosure;

FIG. 4 illustrates a representation of phase tracking reference signal(PTRS) power boosting for coherent UL transmission according to anembodiment of the disclosure;

FIG. 5 illustrates a representation of PTRS power boosting for partiallycoherent UL transmission according to an embodiment of the disclosure;and

FIG. 6 illustrates a representation of PTRS power boosting fornon-codebook-based UL transmission according to an embodiment of thedisclosure.

DETAILED DESCRIPTION

FIGS. 1 through 6, discussed below, and the various embodiments used todescribe the principles of the disclosure in this patent document are byway of illustration only and should not be construed in any way to limitthe scope of the disclosure. Those skilled in the art will understandthat the principles of the disclosure may be implemented in any suitablyarranged system or device.

The disclosure relates to boosting power of certain reference signals ina wireless communication system. It relates particularly, but notexclusively to a 5^(th) generation (5G) or new radio (NR) system,although other systems may benefit. Further it relates particularly tothe phase tracking reference Signal (PTRS or PT-RS), although otherreference signals may benefit. Further, it relates particularly tonon-codebook-based uplink (UL) transmissions.

Terms indicating signals, terms indicating signal propagationcharacteristics (e.g., directivity), terms indicating controlinformation, terms indicating network entities, and terms indicatingcomponents of a device, which are used in the following descriptions,are for the sake of explanations. Accordingly, the disclosure is notlimited to the terms to be described, and may use other terms havingtechnically identical or similar meaning.

In this disclosure, to determine whether a specific condition issatisfied or fulfilled, expressions such as “greater than” or “lessthan” are used by way of example and expressions such as “greater thanor equal to” or “less than or equal to” are also applicable and notexcluded. For example, a condition defined with “greater than or equalto” may be replaced by “greater than” (or vice-versa), a conditiondefined with “less than or equal to” may be replaced by “less than” (orvice-versal), etc.

FIG. 1 illustrates a wireless communication system according to anembodiment. FIG. 1 depicts a base station 110, a terminal 120, and aterminal 130 as some of nodes that use a radio channel in the wirelesscommunication system. While FIG. 1 depicts a single base station,another base station that is the same as or similar to the base station110 may be further included.

The base station 110 is a network infrastructure that provides radioaccess to the terminals 120 and 130. The base station 110 has coveragedefined as a geographical area based on a signal transmission distance.The base station 110 may be referred to as an access point (AP), aneNodeB (eNB), a 5th generation node (5G node), a next generation nodeB(gNB), a wireless point, a transmission/reception point (TRP), or otherterms having a technically equivalent meaning.

The terminal 120 and the terminal 130 are each used by a user andcommunicate with the base station 110 over a radio (or wireless)channel. In some cases, at least one of the terminal 120 and theterminal 130 may operate without a user's involvement. That is, at leastone of the terminal 120 and the terminal 130 may perform machine typecommunication (MTC) and may not be carried by the user. The terminal 120and the terminal 130 each may be referred to as a user equipment (UE), amobile station, a subscriber station, a remote terminal, a wirelessterminal, a user device, or other terms having a technically equivalentmeaning.

The base station 110, the terminal 120, and the terminal 130 maytransmit and receive radio signals (e.g., wireless signals) in amillimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz). Toimprove channel gain, the base station 110, the terminal 120, and theterminal 130 may conduct (or perform) beamforming. Herein, thebeamforming may include transmit beamforming (or transmissionbeamforming) and receive beamforming (or reception beamforming). Thatis, the base station 110, the terminal 120, and the terminal 130 mayapply directivity to a transmit signal or a receive signal. To this end,the base station 110 and the terminals 120 and 130 may select servingbeams 112, 113, 121, and 131 through a beam search or beam managementprocedure. After the serving beams 112, 113, 121, and 131 are selected,communications may be performed using resources that are quasico-located (QCL) with resources used for transmitting the serving beams112, 113, 121, and 131.

If large-scale properties of a channel that carries a symbol on a firstantenna port may be inferred from a channel that carries a symbol on asecond antenna port, the first antenna port and the second antenna portmay be said to be QCL. For example, the large-scale properties mayinclude at least one of delay spread, Doppler spread, Doppler shift,average gain, average delay, and spatial receive parameter.

FIG. 2 illustrates a base station 110 in a wireless communication systemaccording to an embodiment. FIG. 2 depicts a configuration of the basestation 110. In the following description, it is understood that a termsuch as “module”, “unit”, “portion”, “-or” or “-er” indicates a unit forprocessing at least one function or operation, and may be implementedusing hardware, software, or a combination of hardware and software.

Referring to FIG. 2, the base station 110 includes a wirelesscommunication unit 210 (e.g., wireless communicator or wirelesscommunication interface), a backhaul communication unit 220 (e.g.,backhaul communicator or backhaul communication interface), a storageunit 230 (e.g., storage), and a control unit 240 (e.g., at least oneprocessing device).

The wireless communication unit 210 may transmit and receive signalsover a radio (or wireless) channel. For example, the wirelesscommunication unit 210 performs a conversion function between a basebandsignal and a bit string (or bit stream) according to a physical layerstandard of the system. By way of further example, when data istransmitted, the wireless communication unit 210 generates complexsymbols by encoding and modulating a transmit bit string (ortransmission bit stream). Similarly, when data is received, the wirelesscommunication unit 210 restores a receive bit string (or reception bitstream) by demodulating and decoding a baseband signal.

Furthermore, the wireless communication unit 210 up-converts thebaseband signal to a radio frequency (RF) band signal, transmits the RFband signal via an antenna, and down-converts an RF band signal receivedvia an antenna to a baseband signal. To this end, the wirelesscommunication unit 210 may include at least one of a transmit filter, areceive filter, an amplifier, a mixer, an oscillator, a digital toanalog convertor (DAC), an analog to digital convertor (ADC), and thelike. In addition, the wireless communication unit 210 may include orutilize a plurality of transmit (or transmission) and receive (orreception) paths. Further, the wireless communication unit 210 mayinclude at least one antenna array including a plurality of antennaelements.

In terms of hardware, the wireless communication unit 210 may include adigital unit and an analog unit, and the analog unit may include aplurality of sub-units according to an operating power and an operatingfrequency. The digital unit may include at least one processor (e.g., adigital signal processor (DSP)).

As described above, the wireless communication unit 210 transmits andreceives signals. Hence, the entirety or a part of the wirelesscommunication unit 210 may be referred to as a transmitter, a receiver,or a transceiver. Hereinbelow, transmission and the reception over aradio (or wireless) channel may include the above-described processingof the wireless communication unit 210.

The backhaul communication unit 220 provides an interface forcommunicating with other nodes in the network. That is, the backhaulcommunication unit 220 converts a bit sting transmitted from the basestation 110 to another node, for example, to another access node,another base station, an upper node, or a core network, to a physicalsignal, and converts a physical signal received from the other node to abit string.

The storage unit 230 stores data, such as a basic program, anapplication program, configuration information, settings, and the likefor operating the base station. The storage unit 230 may include avolatile memory, a non-volatile memory, or a combination of a volatilememory and a non-volatile memory. The storage unit 230 provides thestored data in response to a request from the control unit 240.

The control unit 240 controls general operations of the base station.For example, the control unit 240 transmits and receives signals throughthe wireless communication unit 210 or the backhaul communication unit220. Also, the control unit 240 records data to the storage unit 230 andreads data from the storage unit 230. The control unit 240 may executefunctions of a protocol stack required by or included in a particularcommunication standard. According to another embodiment, the protocolstack may be included in and/or implemented via the wirelesscommunication unit 210. To this end, the control unit 240 may include atleast one processor.

According to an embodiment, the control unit 240 may determine at leastone beam to communicate with a terminal (e.g., the terminal 120). Forexample, the control unit 240 may determine a transmit (or transmission)beam of the base station 110 based on a feedback from the terminal.Further, the control unit 240 may determine at least one of a receive(or reception) beam of the base station 110 and a transmit beam of theterminal using a signal transmitted from the terminal. Additionally, thecontrol unit 240 may transmit information indicating the determinedtransmit beam of the terminal, to the terminal. For example, the controlunit 240 may control the base station 110 to carry out operationsexplained below according to one or more embodiments.

FIG. 3 illustrates a terminal 120 in a wireless communication systemaccording to an embodiment. In the following description, it isunderstood that a term such as “module”, “unit”, “portion”, “-or” or“-er” indicates a unit for processing at least one function oroperation, and may be implemented using hardware, software, or acombination of hardware and software.

Referring to FIG. 3, the terminal 120 includes a communication unit 310(e.g., communicator or communication interface), a storage unit 320(e.g., storage), and a control unit 330 (e.g., at least one processor).By way of example, the terminal 120 may be a cellular phone or otherdevice that communicates over a cellular network (such as a 5G or pre-5Gnetwork).

The communication unit 310 may transmit and receive signals over a radiochannel. For example, the communication unit 310 performs a conversionfunction between a baseband signal and a bit string according to aphysical layer standard of the system. By way of further example, whendata is transmitted, the communication unit 310 generates complexsymbols by encoding and modulating a transmit bit string. Similarly,when data is received, the communication unit 310 restores a receive bitstring by demodulating and decoding a baseband signal. Furthermore, thecommunication unit 310 up-converts the baseband signal to an RF bandsignal, transmits the RF band signal via an antenna, and down-convertsan RF band signal received via the antenna to a baseband signal. Forexample, the communication unit 310 may include at least one of atransmit filter, a receive filter, an amplifier, a mixer, an oscillator,a DAC, an ADC, and the like.

Also, the communication unit 310 may include or utilize a plurality oftransmit and receive paths. Further, the communication unit 310 mayinclude at least one antenna array including a plurality of antennaelements. In terms of hardware, the communication unit 310 may include adigital circuit and an analog circuit (e.g., an RF integrated circuit(RFIC)). Herein, the digital circuit and the analog circuit may beimplemented as a single package. Also, the communication unit 310 mayinclude a plurality of RF chains. Further, the communication unit 310may perform beamforming.

As described above, the communication unit 310 transmits and receivessignals. Hence, the entirety or a part of the communication unit 310 maybe referred to as a transmitter, a receiver, or a transceiver.Hereinbelow, the transmission and the reception over the radio channelmay include the above-described processing of the communication unit310.

The storage unit 320 stores data, such as a basic program, anapplication program, configuration information, settings, and the likefor operating the terminal. The storage unit 320 may include a volatilememory, a non-volatile memory, or a combination of a volatile memory anda non-volatile memory. The storage unit 320 provides the stored dataaccording to a request from the control unit 330.

The control unit 330 controls general operations of the terminal. Forexample, the control unit 330 transmits and receives signals through thecommunication unit 310. Also, the control unit 330 records data to thestorage unit 320 and reads data from the storage unit 320. The controlunit 330 may execute functions of a protocol stack required by orincluded in a particular communication standard. To this end, thecontrol unit 330 may include at least one processor or microprocessor,or may be part of a processor. Part of the communication unit 310 andthe control unit 330 may be referred to as a communication processor(CP).

According to an embodiment, the control unit 330 may determine at leastone beam for communication with a base station (e.g., the base station110). For example, the control unit 330 may determine at least one of areceive beam of the terminal 120 and a transmit beam of the base stationusing a signal transmitted from the base station. Further, the controlunit 330 may transmit information indicating the determined transmitbeam of the base station, to the base station. For example, the controlunit 330 may determine the transmit beam of the base station based on arequest from the base station. Further, the control unit 330 may controlthe terminal to carry out operations, to be explained below, accordingto one or more embodiments.

In the wireless communication system according to an embodiment, a basestation or a terminal may transmit PTRSs. An agreement about power ofthe PTRS in standardization meetings may be summarized by means of thefollowing table 1 below.

TABLE 1 Full coherent Partial coherent Non-coherent n_(layer) ^(PUSCH)n_(layer) ^(PUSCH) n_(layer) ^(PUSCH) UL-PTRS-power/ 1 2 3 4 1 2 3 4 1 23 4 00 0 3 4.77 6 0 Q Q Q + 3 0 Q Q Q 01 0 3 4.77 6 0 3 4.77 6 0 3 4.776 10 reserved reserved reserved 11 Reserved reserved reserved Note that:Q = 0 for 1 PT-RS port case, Q = 3 for 2 PT-RS port case.

If two PT-RS ports are configured, their energy per resource element(EPREs) are the same. However, for cases where non-codebook-based ULtransmissions are made, there is no agreed standardized approach.Embodiments of the disclosure aim to address issues related to referencesignal boosting in non-codebook-based UL transmissions.

For codebook-based UL transmissions, there may be a constraint on perantenna/antenna-port power constraint because the RF chain cost ishigher without such a constraint and power boosting may be adjusted toinclude such a constraint.

For codebook-based (as opposed to non-codebook-based) UL transmission,it is known exactly whether the transmission is coherent,partially-coherent or non-coherent. For coherent transmission, there isonly one RF chain and the power source is shared by all UL transmissionlayers.

Therefore, such a power constraint does not apply, as illustrated inFIG. 4, where single PTRS port 0 is boosted by 4 times (6 dB), as shownby the enlarged shaded portions 411-414. On the contrary, for partial ornon-coherent cases, there may be multiple RF chains and power sources.FIG. 4 illustrates a fully coherent scenario, with four UL layers. Eachlayer corresponds to a separate data stream, having its own DMRS port.

For instance, four UL transmission layers could be divided into multiplegroups and each group has its own RF chain and power source so that anypower sharing is only possible within each group. In such a case, powerconstraint applies and the power boosting can be performed based on thefirst row (00) of Table 1. This is illustrated in FIG. 5, where a singlePTRS port is configured but its power is not boosted because of the perantenna/antenna-port power constraint. FIG. 5 illustrates a partiallycoherent scenario, where the shaded portions 511 and 512 represent REswhere PTRS is transmitted but power boosting is not permitted.

An issue for the current codebook-based UL transmission power boostingconcerns the second row (01) of Table 1. For the first row (00), thenumber of PTRS ports can be configured as one or two. However, for thesecond row (01), there are some issues. In such a case, it should beconfigured such that the second row can only be configured when one PTRSport is configured, i.e., simultaneous configuration of 2 PTRS ports andUL-PTRS-power=“01” should be forbidden.

Embodiments of the disclosure address the power boosting problem fornon-codebook based UL transmission. For non-codebook based transmission,the base station (gNB) may not be able to ascertain how precoding isperformed by the UE and so therefore does not know if power constraintsapply or not. In such a case, the worst case may be assumed, where theremight be multiple power sources and they cannot be shared. The powerboosting factor needs to be signaled via RRC.

In one embodiment, power can be borrowed from other UL layers where thecorresponding DMRS ports share the same PTRS port.

When only one PTRS port is configured, power boosting may be based onthe number of UL transmission layers, i.e., number of corresponding ULDMRS ports sharing the indicated UL PTRS port, which is essentially thesame as is illustrated in FIG. 4.

When two PTRS ports are configured, there may be only one RF chain sothat the power source can be shared. However, it is also possible thatthere are two RF chains, so that power sharing is not possible.

The gNB does not have such information. As mentioned above, the worstcase needs to be considered in such a case, i.e., power sharing is notpossible. As such, power boosting can be from two sources:

-   -   Muted REs from another PTRS port    -   Muted REs from other UL transmission layers where the        corresponding UL DMRS ports share the same UL PTRS port

As illustrated in FIG. 6, two PTRS ports are configured. DMRS portscorresponding to UE layer 0 and 1 share PTRS port 0 and DMRS portscorresponding to UE layer 2 and 3 share PTRS port 1.

Both PTRS port 0 and 1 can be power boosted due to the muted REsconfigured for the other PTRS port, i.e., port 0 can be boosted due tothe muted REs configured for port 1 and vice-versa.

In addition, it is possible to boost the power further due to the mutedREs from another UE layer where the corresponding DMRS ports share thesame PTRS port.

In FIG. 6, PTRS port 0 is power boosted by a factor of 2 (3 dB), becauseof the muted REs for PTRS port 1 and is further boosted by a factor of 2(3 dB), giving a total of 6 dB because of the muted REs 610 for ULlayer 1. The power boost is represented by the shaded taller bars 611and 612.

Port 1 is power boosted by a factor of 2 (3 dB), because of the mutedREs for PTRS port 0 and is further boosted by a factor of 2 (3 dB),giving a total of 6 dB because of the muted REs 620 for UL layer 3. Thepower boost is represented by the shaded taller bars 621 and 622.

The power boosting ρ_(PTRS,i) for PTRS port i can be expressed as:

ρ_(PTRS,i)=−10 log₁₀(N _(PTRS))−α_(PTRS,i),

where N_(PTRS) is the number of total PTRS ports, and α_(PTRS,i) isshown in Table 2 below which is to be reflected in the standardizationprotocols for NR.

TABLE 2 The number of PUSCH layers where the correspondingPUSCH-to-PT-RS DMRS ports share the same PT-RS port i, (n_(layer)^(PUSCH)) EPRE ratio 1 2 3 4 00 0 3 4.77 6 01 reserved 10 reserved 11reserved

It should be noted that one PTRS port can be associated with onesounding reference signal (SRS) port. One or multiple DMRS port(s) canbe associated with the SRS port. In such a case, it is possible to usethe number of DMRS ports associated with the SRS ports, where the PTRSport index associated with different scheduling request indicator (SRIs)are the same. In such a case, n_(layer) ^(PUSCH) can also be equal tothe number of DMRS ports associated with the SRS ports, where the PTRSport index associated with different SRIs are the same.

In the case of coherence, Table 2 can be modified to give Table 3,below:

TABLE 3 The number of PUSCH layers where the corresponding DMRS portsshare the same PT-RS port i, PUSCH-to-PT-RS (n_(coherentlayer) ^(PUSCH))EPRE ratio 1 2 3 4 00 0 3 4.77 6 01 reserved 10 reserved 11 reserved

where n_(currentlayer) ^(PUSCH) is the number of coherent PUSCH layerswhose corresponding DMRS ports sharing the same PTRS port and it isequal to or smaller than n_(layer) ^(PUSCH).

In another embodiment, the power boosting factor ρ_(PTRS,i) can be afixed value so that

ρ_(PTRS,i)=10 log₁₀(N _(PTRS))

if α_(PTRS,i) is set as 0.

Power boosting is then only decided by number of configured PTRS ports.

Alternatively, the following equation may apply:

ρ_(PTRS,i)=10 log₁₀(N _(PTRS))−α_(PTRS,i).

This leads to Table 4, below:

TABLE 4 The number of PUSCH layers where the correspondingPUSCH-to-PT-RS DMRS ports share the same PT-RS port i, (n_(layer)^(PUSCH)) EPRE ratio 1 2 3 4 00 α α α α 01 reserved 10 reserved 11reserved

where α can be any constant value.

For codebook-based transmission, a UE reports its UE capability as oneof: ‘partialAndNonCoherent’; ‘Non-Coherent’; orfullAndPartialAndNonCoherenr. For non-codebook-based transmission,according to an embodiment of the disclosure, this reporting informationcan also be used.

If the UE reports ‘Non-Coherent’ or does not report, it can be assumedthat the UE can only work for non-coherent case and therefore, the powerboosting factor can be shown to be:

ρ_(PTRS,i=)−10 log₁₀(N _(PTRS)).

If the UE reports fullAndPartialAndNonCoherenr, only one PTRS port canbe configured, based on the agreement, and the power boosting factor isgiven as:

ρ_(PTRS,i)=α_(PTRS,i).

The following table, Table 5, then applies:

TABLE 5 The number of PUSCH layers where the correspondingPUSCH-to-PT-RS DMRS ports share the same PT-RS port i, (n_(layer)^(PUSCH)) EPRE ratio 1 2 3 4 00 0 3 4.77 6 01 reserved 10 reserved 11reserved

If the UE reports ‘partialAndNonCoherent’, it can work either innon-coherent mode or partial-coherent mode. Table 6, below, thenapplies:

TABLE 6 ‘partialAndNonCoherent’ reported UL-PTRS- n_(layer) ^(PUSCH)power/ 1 2 3 4 00 0 10 log₁₀ (N_(PTRS)) 10 log₁₀ (N_(PTRS)) + 10 log₁₀(N_(PTRS)) + 10 log₁₀ (n_(coherentlayer) ^(PUSCH)) 10 log₁₀(n_(coherentlayer) ^(PUSCH)) 01 0 3 4.77 6 10 reserved 11 reserved

Here n_(coherentlayer) ^(PUSCH) is the number of coherent PUSCH layerswhose corresponding DMRS ports share the same PTRS port.

The previous tables can be combined and represented by the followingaggregate table, Table 7. This is similar to table 6.2.3.1-3 shown in38.214 [NR; Physical layer procedures for data].

TABLE 7 The number of PUSCH layers (n_(layer) ^(PUSCH)) 2 UL-PTRS- 1Partial and 3 4 power/ All Full non- Full non- Full α_(PTRS) ^(PUSCH)cases coherent coherent coherent Partial coherent coherent coherentPartial coherent Non-coherent 00 0 3 3Q_(p)-3 4.77 10 log₁₀(N_(PTRS)) +3Q_(p)-3 6 10 log₁₀(N_(PTRS)) + 3Q_(p)-3 10 log₁₀(n_(coherentlayer)^(PUSCH)) 10 log₁₀(n_(coherentlayer) ^(PUSCH)) 01 0 3 3 4.77 4.77 4.77 66 6 10 Reserved 11 Reserved

where n_(layer) ^(PUSCH) is the number of PUSCH layers where thecorresponding DMRS ports share the same PT-RS port i, andn_(coherentlayer) ^(PUSCH) is the number of UL transmission layers whichare coherent with each other and these UL layers contain the layerassociated with the PTRS port.

In an alternative embodiment, the UE checks its own precoding matrix toidentify the coherence of PUSCH layers. It then reports this to the gNB,which instructs the UE on the appropriate power boosting values based ontable 6. Here, n_(coherentlayer) ^(PUSCH) can be estimated by the numberof DMRS ports associated to the same SRS port.

Another approach to handle “partialAndNonCoherent” case is to assumenon-coherent and thus power can only be borrowed from muted REs fromanother PTRS port. In such a case, the power boost factor can berepresented as:

ρ_(PTRS,i)=−10 log₁₀(N_(PTRS)).

This is reflected in the following table, Table 8:

TABLE 8 ‘partialAndNonCoherent’ reported UL-PTRS- n_(layer) ^(PUSCH)power/ 1 2 3 4 00 0 10 log₁₀ (N_(PTRS)) 10 log₁₀ (N_(PTRS)) 10 log₁₀(N_(PTRS)) 01 0 3 4.77 6 10 reserved 11 reserved

In another embodiment, instead of the gNB deciding on the powerboosting, the UE is operable to determine and configure it independentlyof the gNB. In particular, the gNB might not have all necessaryinformation, e.g, n_(coherentlayer) ^(PUSCH). In such cases, powerboosting can be decided by the UE based on its own precoding matrix,from which UE can identify n_(coherentlayer) ^(PUSCH).

It should be noted that some or all of the embodiments of the disclosuremay violate the agreement in RAN1 (the Radio layer definition in NR)that symbols with and without PTRS should have the same power in UL. Assuch, there are two alternative solutions:

-   -   Scale the power of the symbol with PTRS including PTRS and PUSCH        to the same level as the symbol without PTRS, e.g., {circumflex        over (ρ)}_(PTRS,i)=βρ_(PTRS,i), where β is the scaling factor.    -   Scale up the power of the symbol without PTRS including PUSCH to        the same level as the symbol with PTRS and PUSCH. This can be        performed in the UE, as required.

A possible issue of power shortage may arise where the PTRS symbol poweris attempted to be boosted to a level higher than the maximum powerlevel that the UE can support. In such a case, it is preferable toreduce the power of PUSCH in the same antenna port and use this ‘spare’power to provide the power for the PTRS power boosting.

The UE can decide to choose either power scaling or it may puncturePUSCH and use the power from PUSCH to provide the power for boostingPTRS.

It should also be noted that multiple different implementations may besupported by selectively merging one or more of the tables presented inthis application.

Throughout this application, reference has been made to the PTRSreference signal, but it should be noted that the same principles applyto other reference signals—such as CSI-RS, DMRS, SRS and TRS—in the NRspecification and that these other reference signals may also benefitfrom power boosting according to embodiments of the disclosure.

At least some of the example embodiments described herein may beconstructed, partially or wholly, using dedicated special-purposehardware. Terms such as ‘component’, ‘module’ or ‘unit’ used herein mayinclude, but are not limited to, a hardware device, such as circuitry inthe form of discrete or integrated components, a Field Programmable GateArray (FPGA) or Application Specific Integrated Circuit (ASIC), whichperforms certain tasks or provides the associated functionality. In someembodiments, the described elements may be configured to reside on atangible, persistent, addressable storage medium and may be configuredto execute on one or more processors. These functional elements may insome embodiments include, by way of example, components, such assoftware components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables. Although the example embodiments have been described withreference to the components, modules and units discussed herein, suchfunctional elements may be combined into fewer elements or separatedinto additional elements. Various combinations of optional features havebeen described herein, and it will be appreciated that describedfeatures may be combined in any suitable combination. In particular, thefeatures of any one example embodiment may be combined with features ofany other embodiment, as appropriate, except where such combinations aremutually exclusive. Throughout this specification, the term “comprising”or “comprises” means including the component(s) specified but not to theexclusion of the presence of others.

Attention is directed to all papers and documents which are filedconcurrently with or previous to this specification in connection withthis application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings) may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Although the disclosure has been described with various embodiments,various changes and modifications may be suggested to one skilled in theart. It is intended that the disclosure encompass such changes andmodifications as fall within the scope of the appended claims. cm Whatis claimed is:

1. A method for operating a user equipment (UE) in a wirelesscommunication system, the method comprising: determining power of atleast one phase tracking reference signal (PT-RS); and transmitting theat least one PT-RS according to non-codebook based transmission, whereinthe power is determined based on a number of at least one port for theat least one PT-RS.
 2. The method of claim 1, wherein the determiningthe power of at least one PT-RS comprises: borrowing power from mutedresource elements (REs) based on a configuration of another referencesignal port; or borrowing power from the muted REs based on theconfiguration of another reference signal port and power borrowingbetween uplink transmission layers where corresponding demodulationreference signal (DMRS) ports share the same phase tracking or soundingreference signal (SRS) port.
 3. The method of claim 1, wherein a powerboosting factor ρ_(PTRS,i) for PTRS port i is expressed as:ρ_(PTRS,i)=−10 log₁₀(N _(PTRS))−α_(PTRS,i) where N_(PTRS)=number oftotal PTRS ports, α_(PTRS,i) is shown in row 00 of the table below: Thenumber of PUSCH layers where the corresponding PUSCH-to-PT-RS DMRS portsshare the same PT-RS port i, (n_(layer) ^(PUSCH)) EPRE ratio 1 2 3 4 000 3 4.77 6 01 reserved 10 reserved 11 reserved


4. The method of claim 1, wherein the power is boosted based onborrowing power from the muted REs based on a configuration of anotherPTRS port and a fixed power boosting factor.
 5. The method of claim 1,wherein the power is boosted based on a UE capability report relating tosupport of coherent precoding, partial-coherent precoding, ornon-coherent precoding.
 6. The method of claim 5, wherein, if the UEcapability report indicates non-coherent precoding or does not reportprecoding, the power boosting factor is:ρ_(PTRS,i)=−10 log₁₀(N _(PTRS)).
 7. The method of claim 5, wherein, ifthe UE capability report indicates coherent precoding andpartial-coherent precoding and non-coherent precoding only one PTRS portis configured and the power boosting factor is:ρ_(PTRS,i)=α_(PTRS,i), where α_(PTRS,i) is shown in row 00 of the tablebelow: The number of PUSCH layers where the corresponding PUSCH-to-PT-RSDMRS ports share the same PT-RS port i, (n_(layer) ^(PUSCH)) EPRE ratio1 2 3 4 00 0 3 4.77 6 01 reserved 10 reserved 11 reserved


8. The method of claim 5, wherein, if the UE capability report indicatespartial-coherent precoding and non-coherent precoding the UE can operatein either non-coherent mode or partial-coherent mode, and the followingtable applies: ‘partialAndNonCoherent’ reported UL-PTRS-n_(co□erentlayer) ^(PUSCH) power/ 1 2 3 4 00 0 10log₁₀ (N_(PTRS))10log₁₀ (N_(PTRS)) 10log₁₀ (N_(PTRS)) 01 0 3 4.77 6 10 reserved 11reserved

where n_(coherentlayer) ^(PUSCH) is the number of coherent PUSCH layerswhose corresponding DMRS ports share the same PTRS port.
 9. The methodof claim 1, wherein the determining the power of at least one PT-RScomprises: determining the power based on a precoding matrix for the UE,from which the UE identifies a number of coherent physical uplink sharedchannel (PUSCH) layers whose corresponding DMRS ports sharing the samePT-RS port.
 10. The method of claim 1, further comprising: performingpower scaling is applied, if a power shortage occurs.
 11. A userequipment (UE) in a wireless communication system, the UE comprising: atransceiver; and at least one processor coupled to the transceiver andconfigured to: determine power of at least one phase tracking referencesignal (PT-RS); and transmit the at least one PT-RS according tonon-codebook based transmission, wherein the power is determined basedon a number of at least one port for the at least one PT-RS.
 12. The UEof claim 11, wherein the at least one processor is further configuredto: borrow power from muted Resource Elements (REs) due to configurationof another reference signal port; or borrow power from muted REs due toconfiguration of another reference signal port and borrowing powerbetween uplink transmission layers where corresponding demodulationreference signal (DMRS) ports share the same phase tracking or soundingreference signal (SRS) port.
 13. The UE of claim 11, wherein a powerboosting factor ρ_(PTRS,i) for PTRS port i is expressed as:ρ_(PTRS,i)=−10 log₁₀(N _(PTRS))−α_(PTRS,i) where N_(PTRS)=number oftotal PTRS ports, α_(PTRS,i) is shown in row 00 of the table below: Thenumber of PUSCH layers where the corresponding PUSCH-to-PT-RS DMRS portsshare the same PT-RS port i, (n_(layer) ^(PUSCH)) EPRE ratio 1 2 3 4 000 3 4.77 6 01 reserved 10 reserved 11 reserved


14. The UE of claim 11, wherein the at least one processor is furtherconfigured to boost power based on borrowing power from muted REs due toconfiguration of another PTRS port and a fixed power boosting factor.15. The UE of claim 11, wherein the at least one processor is furtherconfigured to boost power based on a UE capability report relating tosupport of coherent precoding, partial-coherent precoding, ornon-coherent precoding.
 16. The UE of claim 15, wherein, if the UEcapability report indicates non-coherent precoding or does not reportprecoding, the power boosting factor is:ρ_(PTRS,i)=−10 log₁₀(N _(PTRS)).
 17. The UE of claim 15, wherein, if theUE capability report indicates coherent precoding and partial-coherentprecoding and non-coherent precoding only one PTRS port is configuredand the power boosting factor is:ρ_(PTRS,i)=α_(PTRS,i), where α_(PTRS,i) is shown in row 00 of the tablebelow: The number of PUSCH layers where the corresponding PUSCH-to-PT-RSDMRS ports share the same PT-RS port i, (n_(layer) ^(PUSCH)) EPRE ratio1 2 3 4 00 0 3 4.77 6 01 reserved 10 reserved 11 reserved


18. The UE of claim 15, wherein, if the UE capability report indicatesnon-coherent precoding and partial-coherent precoding the UE can operatein either non-coherent mode or partial-coherent mode, and the followingtable applies: ‘partialAndNonCoherent’ reported UL-PTRS-n_(coherentlayer) ^(PUSCH) power/ 1 2 3 4 00 0 10log₁₀ (N_(PTRS))10log₁₀ (N_(PTRS)) 10log₁₀ (N_(PTRS)) 01 0 3 4.77 6 10 reserved 11reserved

where n_(coherentlayer) ^(PUSCH) is the number of coherent PUSCH layerswhose corresponding DMRS ports share the same PTRS port.
 19. The UE ofclaim 11, wherein the at least one processor is further configured todetermines the power based on a precoding matrix for the UE, from whichthe UE identifies a number of coherent physical uplink shared channel(PUSCH) layers whose corresponding DMRS ports sharing the same PT-RSport.
 20. The UE of claim 11, wherein the at least one processor isfurther configured to apply power scaling, if a power shortage occurs.